Tribenzoyl compounds

ABSTRACT

An oxygen scavenging composition or system is provided comprising an oxygen scavenging material, a photoinitiator, and at least one catalyst effective in catalyzing an oxygen scavenging reaction, wherein the photoinitiator comprises a benzophenone derivative containing at least two benzophenone moieties. A film, a multi-phase composition, a multi-layer composition, a multi-layer film, an article comprising the oxygen scavenging composition, a method for preparing the oxygen scavenging composition, and a method for scavenging oxygen are also provided. Non-extractable benzophenone derivative photoinitiators and methods for preparing same are also provided.

FIELD OF THE INVENTION

[0001] The present invention relates to photoinitiators, methods forpreparing and using same, oxygen scavenging compositions, articles madefrom same and methods of scavenging oxygen.

BACKGROUND OF THE INVENTION

[0002] The term “oxygen scavenging” means to absorb, deplete, or reactwith oxygen from a given environment.

[0003] Oxygen scavenging materials have been developed partly inresponse to the food industry's goal of having longer shelf-life forpackaged food. One method which is currently being employed involves theuse of “active packaging” where the package is modified in some way soas to control the exposure of the product to oxygen. Such “activepackaging” can include sachets containing iron-based compositions suchas AGELESS™ which scavenges oxygen within the package through anoxidation reaction. However, such an arrangement is not advantageous fora variety of reasons including the accidental ingestion of the sachetsor the oxygen scavenging material present therein.

[0004] Other techniques involve incorporating an oxygen scavenger intothe package structure itself. In such an arrangement, oxygen scavengingmaterials constitute at least a portion of the package, and thesematerials remove oxygen from the enclosed package volume which surroundsthe product or which may leak into the package, thereby, in the case offood products, inhibiting spoilage and prolonging freshness.

[0005] Oxygen scavenging materials include low molecular-weightoligomers that are typically incorporated into polymers or can beoxidizable organic polymers. Such oxygen scavenging materials aretypically employed with a suitable catalyst, e.g., an organic orinorganic salt of a transition metal catalyst.

[0006] The onset of useful oxygen scavenging activity may not occur foras long as 30 days. In order to shorten the induction period and toinitiate oxygen scavenging, photoinitiators can be employed inconjunction with actinic radiation. Many of these photoinitiators andresulting by-products are extractable and can leach into the headspacesurrounding the packaged product or even enter the product itself. Suchleaching can produce foul odors or unpleasant taste or can be otherwiseundesirable.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a compositioneffective for oxygen scavenging under typical storage conditions.

[0008] It is another object of the present invention to provide acomposition which is effective for oxygen scavenging at lowtemperatures.

[0009] It is another object of the present invention to provide anoxygen scavenging composition which produces reduced levels ofextractable compounds.

[0010] It is another object of the present invention to provide anoxygen scavenging composition which has a short initiation period uponactivation.

[0011] It is another object of the present invention to provide anoxygen scavenging composition which exhibits improved shelf life priorto activation.

[0012] It is another object of the present invention to provide a filmor a multi-layer film capable of scavenging oxygen.

[0013] It is another object of the present invention to provide anarticle, package or container suitable for oxygen scavenging.

[0014] It is another object of the present invention to provide a methodfor preparing an oxygen scavenging composition.

[0015] It is another object of the present invention to provide a methodfor scavenging oxygen.

[0016] It is another object of the present invention to provide novelphotoinitiators which are effective initiators for oxygen scavenging.

[0017] It is another object of the present invention to provide novelphotoinitiators which are essentially non-leachable.

[0018] It is another object of the present invention to provide methodsfor preparing novel photoinitiators.

[0019] According to the present invention, an oxygen scavengingcomposition or system is provided comprising an oxygen scavengingmaterial, a photoinitiator, and at least one catalyst effective incatalyzing the oxygen scavenging reaction. The photoinitiator comprisesa benzophenone derivative containing at least two benzophenone moieties.A film, a multi-phase composition, a multi-layer composition, amulti-layer film, an article comprising the oxygen scavengingcomposition, as well as a method for preparing the oxygen scavengingcompositions, and a method for scavenging oxygen are also provided.

[0020] According to other aspects of the present invention,non-extractable photoinitiators and methods for preparing same areprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]FIGS. 1, 2 and 3 are a graphic representation of the effectivenessof various photoinitiators.

DETAILED DESCRIPTION OF THE INVENTION

[0022] It has been found that benzophenone derivatives containing atleast two benzophenone moieties act as effective photoinitiators toinitiate oxygen scavenging activity in oxygen scavenging compositionsand to provide a composition having a very low degree of extraction ofthe photoinitiators which may contaminate a packaged product. Bybenzophenone moiety is meant a substituted or unsubstituted benzophenonegroup. Suitable substituents are any substituent which does notinterfere with the objects of the invention and include alkyl, aryl,alkoxy, phenoxy, and alicylic groups containing from 1 to 24 carbonatoms or halides.

[0023] These derivatives are substantially non-extractable by mostorganic solvents at room temperature. By substantially non-extractableis meant that less than about 500 ppb photoinitiator are extractedthrough a 0.5 mil polyethylene film in ten days at room temperature froman oxygen scavenging composition containing 1000 ppm by weightphotoinitiator when exposed to 10 g fatty food simulant per square inchof 1 mil film, preferably 250 ppb photoinitiator or less are extracted,more preferably 100 ppb photoinitiator or less are extracted, and mostpreferably 50 ppb photoinitiator or less are extracted.

[0024] Such benzophenone derivatives include dimers, trimers, tetramers,and oligomers of benzophenone-type photoinitiators derived frombenzophenone and substituted benzophenones, as fully described hereinbelow.

[0025] The substantially non-extractable photoinitiators are representedby the following formula:

X_(m)(Y)_(n)

[0026] Wherein each X is a bridging group selected from the groupconsisting of sulfur; oxygen; carbonyl; —SiR₂—, wherein each R isindividually selected and is an alkyl group containing from 1 to 12carbon atoms, an aryl group containing 6 to 12 carbon atoms, or analkoxy group containing from 1 to 12 carbon atoms; —NR′—, wherein R′ isan alkyl group containing 1 to 12 carbon atoms, aryl group containing 6to 12 carbon atoms, or hydrogen; and an organic group containing from 1to 50 carbon atoms, preferably from 1 to 40 carbon atoms. X can be adivalent group or can be a polyvalent group with 3 or more benzophenonemoieties attached. Wherein m is 0 to 11.

[0027] The organic bridging group, when present, can be linear,branched, cyclic including fused or separate cyclic groups or an arylenegroup which can be fused or non-fused polyaryl groups. The organicbridging group can contain one or more heteroatoms such as oxygen,nitrogen, phosphorous, silicon or sulfur or combinations thereof. Oxygencan be present as an ether, ketone, ester, or alcohol.

[0028] Wherein each Y is a substituted or unsubstituted benzophenonegroup. Wherein each substituent, R″, when present, is individuallyselected from any substituent which does not substantially interferewith the objects of the invention and include alkyl, aryl, alkoxy,phenoxy, or alicylic groups containing from 1 to 24 carbon atoms, orhalides. Each benzophenone moiety can have up to 9 substituents. Whereinn is 2-12.

[0029] Preferably, the combined molecular weight of the X and R″ groupsis at least about 30 g/mole. Appropriate choice of substituents canrender the photoinitiator more compatible with the oxygen scavengingcomposition. Such substituents include alkyl and alkoxy for example.

[0030] Preferably, the oxygen scavenging composition consumes half ofthe available oxygen in a container containing 1 percent oxygen in lessthan 4 days at 25° C. More preferably, the oxygen scavenging compositionconsumes half of the available oxygen in a container containing 1percent oxygen in less than 4 days at 4° C.

[0031] The photoinitiators include multiplets of ultraviolet (UV)initiators linked by cross conjugation so as to retain the UV absorptioncharacteristics with enhanced UV absorptivity, i.e., higher extinctioncoefficient. The linkages within the dimers, trimers, tetramers, andoligomers can be flexible or rigid. The rigid type are preferred forlower extractability. However, a certain degree of flexibility isrequired to facilitate the melt blending to allow a molecular leveldistribution in the polymer films.

[0032] Typically, these compounds have a strong UV absorption at about200-400 nm. Generally, the molecular weight will be greater than about360 g/mole, preferably in the range of from about 360 g/mole to about5000 g/mole, more preferably in the range of from 390 g/mole to 4000g/mole.

[0033] The photoinitiators are substantially non-extractable by mostorganic solvents when incorporated into oxygen scavenging compositions.They provide efficient light absorption to trigger a photochemicalinduced oxidation. The photoinitiators are stable and do not fragmentinto extractable by-products. The photoinitiators are also large enoughor rigid enough to be immobile and therefore cannot be leached into thepackaged food or product. The photoinitiators do not sublime undernormal processing and handling conditions. This assures an extendedshelf life for the preactivated composition and a safe packagingmaterial according to U.S. Food and Drug Administration standards.

[0034] Examples of non-extractable photoinitiators include dibenzoylbiphenyl, substituted dibenzoyl biphenyl, benzoylated terphenyl,substituted benzoylated terphenyl, tribenzoyl triphenylbenzene,substituted tribenzoyl triphenylbenzene, benzoylated styrene oligomer,and substituted benzoylated styrene oligomer. Benzoylated styreneoligomer is a mixture of compounds containing from 2 to 12 repeatingstyrenic groups comprising dibenzoylated 1,1-diphenyl ethane,di-benzoylated 1,3 diphenyl propane, di-benzoylated 1-phenylnaphthalene, dibenzoylated styrene dimer, dibenzoylated styrene trimerand tribenzoylated styrene trimer.

[0035] Suitable substituents for the above compounds include anysubstituent which does not interfere substantially with the objects ofthe invention and include alkyl, aryl, alkoxy, phenoxy, and alicylicgroups containing from 1 to 24 carbon atoms or halides.

[0036] Typical examples of suitable alkyl groups include methyl, ethyl,propyl, isopropyl, butyl, t-butyl, pentyl, dodecyl, hexadecyl, octadecyland the like. Specific examples of alkoxy groups include methoxy,ethoxy, propoxy, butoxy, dodecyloxy and the like. Examples of alicyclicgroups include cyclopentyl, cyclohexyl, cycloheptyl and the like. Thehydrocarbon substituents can be saturated or can contain ethylenicunsaturation.

[0037] Examples of specific photoinitiators include4,4′-bis(4,4′-dimethyidibenzoyl) biphenyl;4,4′-bis(4,4′-diethyidibenzoyl) biphenyl;4,4′-bis(2,2′-dimethyldibenzoyl) biphenyl;4,4′-bis(2,2′-dimethoxydibenzoyl) biphenyl; 4,4′-bis(4-dodecyidibenzoyl)biphenyl; 4,4′-bis(2,2′-diacetyldibenzoyl) biphenyl;4,4-bis(4,4′-dimethyldibenzoyl) diphenyl ether;4,4′-bis(4,4′-diethyidibenzoyl) diphenyl ether;4,4′-bis(2,2-dimethyldibenzoyl) diphenyl ether;4,4′-bis(2,2′-dimethoxydibenzoyl) diphenyl ether;4,4′-bis(4-dodecyldibenzoyl) diphenyl ether;4,4′-bis(2,2′-diacetyldibenzoyl)diphenyl ether;4,4′-bis(4,4′-dimethyldibenzoyl)diphenyl sulfide;4,4′-bis-diethyldibenzoyl)diphenyl sulfide;4,4′-bis(2,2′-dimethyldibenzoyl)diphenyl sulfide;4,4′-bis(2,2′-dimethoxydibenzoyl) diphenyl sulfide;4,4′-bis(4-dodecyldibenzoyl) diphenyl sulfide;4,4′-bis(2,2′-diacetyldibenzoyl) diphenyl sulfide;4,4′-bis(4,4′-dimethyldibenzoyl) diphenyl amine;4,4′-bis(4,4′-diethyldibenzoyl) diphenyl amine;4,4-bis(2,2′-dimethyidibenzoyl) diphenyl amine;4,4′-bis(2,2′-dimethoxydibenzoyl) diphenyl amine;4,4′-bis(4-dodecyldibenzoyl) diphenyl amine:4,4′-bis(2,2′-diacetyidibenzoyl) diphenyl amine;4,4′-bis(4,4′-dimethyidibenzoyl) diphenyl dimethyl silane;4,4′-bis(4,4′-diethyidibenzoyl) diphenyl dimethyl silane;4,4′-bis(2,2′-dimethyidibenzoyl) diphenyl dimethylsilane;4,4′-bis(2,2′-dimethoxydibenzoyl) diphenyl dimethyl silane;4,4′-bis(4-dodecyldibenzoyl) diphenyl dimethyl silane;4,4′-bis(2,2′-diacetyldibenzoyl) diphenyl dimethyl silane;4,4′-bis(4,4′-dimethyldibenzoyl) benzophenone;4,4′-bis(4,4′-diethyldibenzoyl) benzophenone;4,4′-bis(4,4′-dipropyidibenzoyl) benzophenone;4,4′-bis(2,2′-dimethoxydibenzoyl) benzophenone;4,4′-bis(4-dodecyldibenzoyl) benzophenone;4,4-bis(2,2′-diacetyldibenzoyl) benzophenone;4,4′-bis(4,4′-dimethyldibenzoyl) diphenyl methane;4,4′-bis(4,4′-diethyidibenzoyl) diphenyl methane;4,4′-bis(4,4′-dipropyldibenzoyl) diphenyl methane;4,4′-bis(2,2′-dimethoxydibenzoyl) diphenyl methane;4,4-bis(4-dodecyidibenzoyl) diphenyl methane;4,4′-bis(2,2′-diacetyldibenzoyl) diphenyl methane;4,4′-dibenzoyl-1,4-diphenoxy butane; 4,4′-dibenzoyl-1,2-diphenoxyethane; 4,4′-bis(4,4′-dimethyidibenzoyl)-1,4-diphenoxy butane;4,4′-dibenzoyl-1,12-diphenoxy-dodecane; tritoluoyl triphenyl benzene,tri(para-methoxybenzoyl) triphenyl benzene, dibenzoyl meta-terphenyl,ditoluoyl meta-terphenyl, ditoluoyl para-terphenyl, diethyldibenzoylmeta-terphenyl, dipropyldibenzoyl ortho-terphenyl, dibutyidibenzoylpara-terphenyl, dipentyidibenzoyl meta-terphenyl, dihexyldibenzoylortho-terphenyl, diheptyldibenzoyl para-terphenyl, dioctyldibenzoylmeta-terphenyl, dioctadecyl dibenzoyl ortho-terphenyl, and the like.

[0038] The photoinitiator is present in an amount sufficient to decreasethe induction period after UV triggering. The amount of photoinitiatoremployed can vary broadly depending on the oxygen scavenging materialemployed, the wavelength, time of exposure and intensity of theradiation used, the type of photoinitiator, time of exposure and theamount of antioxidants employed, if any.

[0039] Generally, the photoinitiator will be present in an amount in therange of from about 0.001 weight percent to about 10 weight percentbased on the total weight of the oxygen scavenging composition,preferably from 0.005 weight percent to 5 weight percent, and morepreferably from 0.01 weight percent to 1 weight percent.

[0040] An effective photoinitiator is one which provides the oxygenscavenging composition an induction period of one day or less. Thephotoinitiator should be effective at 25° C. and preferably alsoeffective at 4° C.

[0041] The photoinitiator can be introduced into the oxygen scavengingcomposition by any method known in the art such as coating techniquesand extrusion compounding (including masterbatching). Thephotoinitiators can be introduced into polymers under conventional meltprocessing conditions to provide good mixing without plate-out on themachine.

[0042] The photoinitiator tribenzoyl triphenylbenzene can be prepared byreacting a benzoyl halide, such as benzoyl chloride, and atriphenylbenzene. The benzoyl halide and triphenylbenzene can containadditional substituents. Suitable substituents comprise any substituentwhich does not interfere substantially with the reaction and includealkyl, aryl, alkoxy, phenoxy, and alicylic groups containing from 1 to24 carbon atoms or halides.

[0043] Preferably, an aluminum- or boron-containing catalyst such asaluminum trichloride or boron trifluoride is employed.

[0044] Conditions for reacting the benzoyl chloride and triphenylbenzenecan vary broadly. Generally, the reaction temperature is in the range offrom about −20° C. to about 150° C., preferably from about −10° C. toabout 120° C. The pressure is not critical and ambient pressure issuitable. Typically, the reaction would be conducted in a suitablediluent such as nitrobenzene, chlorobenzene, dichlorobenzene,dichloromethane, dichloroethane, trichloroethane, or carbon disulfide.

[0045] The photoinitiator benzoylated styrene oligomer can be preparedby reacting styrene trimers with a benzoyl halide, such as benzoylchloride. Styrene trimers can be distilled from a polystyreneby-products stream. The benzoyl halide and styrene trimers can containadditional substituents. Suitable substituents comprise any substituentwhich does not interfere substantially with the reaction and includealkyl, aryl, alkoxy, phenoxy, and alicylic groups containing from 1 to24 carbon atoms or halides.

[0046] Preferably, an aluminum- or boron-containing catalyst such asaluminum trichloride or boron trifluoride is employed.

[0047] The reaction produces a mixture of products including the majorcomponents di-benzoylated styrene trimer, tri-benzoylated styrenepentamer, tetra-benzoylated styrene pentamer, di-benzoylated styrenedimer, and minor components including benzoylated 1-phenyl naphthalene,benzoylated styrene dimer, di-benzoylated 1,3 di-phenyl propane,di-benzoylated 1-phenyl naphthalene, benzoylated 1,1-di-phenyl ethane,and benzoylated ethyl-benzene.

[0048] Conditions for reacting the benzoyl halide and styrene trimerscan vary broadly. Generally, the reaction temperature is in the range offrom about 0° C. to about 100° C. The pressure is not critical andambient pressure is suitable.

[0049] The photoinitiator benzoylated terphenyl can be prepared byreacting a terphenyl and a benzoyl halide, such as benzoyl chloride. Theterphenyl can be para-, meta- or ortho-terphenyl. The terphenyl andbenzoyl halide can contain additional substituents. Suitablesubstituents comprise any substituent which does not interferesubstantially with the reaction and include alkyl, aryl, alkoxy,phenoxy, and alicylic groups containing from 1 to 24 carbon atoms orhalides.

[0050] Generally, a catalyst such as aluminum chloride is employed. Thereaction is generally conducted in a suitable solvent such asnitrobenzene, chlorobenzene, dichlorobenzene, dichloromethane,dichloroethane, trichloroethane, or carbon disulfide.

[0051] Conditions for reacting the terphenyl and benzoyl halide can varybroadly. Generally, the reaction temperature is in the range of fromabout 0° C. to about 100° C. The product comprising di-benzoylatedterphenyl can be isolated by recrystalization from toluene.

[0052] The oxygen scavenging material can be any material known in theart to scavenge oxygen, providing that the material does not competestrongly for UV absorption in the critical region where thephotoinitiator absorbs light. The oxygen scavenging material can be anyorganic compound or polymer which contains an oxidizable site. Preferredcompounds include ethylenically unsaturated compounds and thosecontaining benzylic, allylic and/or tertiary hydrogen. Examples of suchorganic compounds include squalene, dehydrated castor oil, polybutene orpolypropylene.

[0053] Substituted oxidizable polymers include polymers and copolymerscontaining esters, carboxylic acids, aldehydes, ethers, ketones,alcohols, peroxides, and/or hydroperoxides. Preferably, the oxidizablepolymers contain two or more ethylenically unsaturated sites permolecule, more preferably three or more ethylenically unsaturated sitesper molecule.

[0054] Other oxidizable compounds suitable as oxygen scavengingmaterials include those described in U.S. Pat. Nos. 5,211,875 and5,346,644 to Speer et al., which are hereby incorporated by reference intheir entirety. Examples of oxidizable compounds include polybutadiene,polyisoprene, styrene-butadiene block copolymers, polyterpenes,poly(meta-xyleneadipamide) (also known as MXD6), polymers of fatty acidssuch as oleic, ricinoleic, dehydrated ricinoleic, and linoleic acids andesters of such acids, acrylates which can be prepared bytransesterification of poly(ethylene-methyl acrylate) such aspoly(ethylene-methyl acrylate-benzyl acrylate), poly(ethylene-methylacrylate-tetrahydrofurfuryl acrylate), poly(ethylene-methylacrylate-nopol acrylate) and mixtures thereof. Such transesterificationprocesses are disclosed in U.S. Ser. No. 08/475,918 filed Jun. 7, 1995,the disclosure of which is hereby incorporated by reference. Butadienepolymers and copolymers, such as styrene-butadiene-styrene blockcopolymer, are preferred for low temperature applications requiringtransparency.

[0055] The polyterpenes such as poly(alpha-pinene), poly(dipentene),poly(beta-pinene), and poly(limonene)are especially effective oxygenscavenger materials and produce reduced amounts of migratory carboxylicacids, aldehydes and alkenes which can produce objectionable odors andtastes.

[0056] The oxygen scavenging material can be introduced into the oxygenscavenging system by a variety of techniques. The oxygen scavengingmaterial can be formed into films which can be a separate layer in amulti-layer structure, coated or laminated onto a material such asaluminum foil or paper, formed into bottles or other rigid containers,or even incorporated into a material such as paper, for example, inflexible and rigid packaging. The oxygen scavenging material can also bein a localized area on a layer; for example, it may be in a patch thatis laminated to another layer. The oxygen scavenging composition cancontain a mixture of two or more oxidizable organic compounds.

[0057] The oxygen scavenging material is generally present in the oxygenscavenging composition in an amount sufficient to scavenge at least 0.1cc O₂/gram of oxygen scavenging composition/day at 25° C. Preferably, itis capable of scavenging at least about 0.5 cc O₂, and more preferablyat least about 1 cc O₂/gram of oxygen scavenging composition/day at 25°C. For many applications, such as food and beverage storage, it isdesirable to select an oxygen scavenging material which will effectivelyscavenge oxygen as indicated at a temperature of 4° C.

[0058] The amount of oxygen scavenging material employed in the oxygenscavenging composition can vary broadly depending on the desiredcharacteristics of the final product. Generally, the oxygen scavengingmaterial is present in an amount in the range of from about 1 weightpercent to about 99 weight percent based on the total oxygen scavengingcomposition, preferably from about 5 weight percent to about 95 weightpercent, and more preferably from 10 weight percent to 90 weightpercent.

[0059] The catalyst can be any catalyst known in the art which iseffective in initiating the oxygen scavenging reaction. Typicalcatalysts include transition metal salts. Suitable catalysts aredisclosed in U.S. Pat. Nos. 5,211,875 and 5,346,644 to Speer et al., thedisclosures of which were previously incorporated by reference in theirentirety. Suitable transition metal salts are those which containmanganese, iron, cobalt, nickel, copper, rhodium, and ruthenium,preferably iron, nickel copper, manganese or cobalt.

[0060] Cobalt compounds containing organic or inorganic anions arepreferred. Suitable anions include chloride, acetate, stearate,caprylate, palmitate, 2-ethylhexanoate, citrate, glycolate, benzoate,neodecanoate, naphthenate, oleate, and linoleate. Organic anions arepreferred and cobalt oleate, cobalt linoleate, cobalt neodecanoate,cobalt stearate and cobalt caprylate are especially preferred. It hasbeen found that a composition comprising the combination of cobaltstearate and benzoylated styrene oligomer is especially effective atscavenging oxygen at low temperature and oxygen levels, e.g., 1% oxygenlevels at 4° C.

[0061] The catalyst is present in an amount sufficient to catalyze theoxygen scavenging reaction. Generally, the catalyst will be present inan amount in the range of from about 10 parts per million by weight(ppm) to about 10,000 ppm by weight transition metal ion based on thetotal weight of the oxygen scavenging composition, preferably from 10ppm to 5,000 ppm transition metal ion.

[0062] The catalyst can be introduced in any manner which does not reactwith and/or deactivate the catalyst. For example, the catalyst can beapplied onto the oxygen scavenging material by any suitable means, e.g.,coating techniques such as spray coating, extrusion compounding orlamination. Further, the catalyst may be included as part of acompounded master batch using a suitable carrier resin.

[0063] The oxygen scavenging composition can be activated by methodsknown in the art such as by actinic radiation, i.e., ultraviolet orvisible light having a wave length in the range of from about 200 nm toabout 750 nm, electron beam, or thermal triggering. Such methods aredescribed in U.S. Pat. No. 5,211,875, the disclosure of which is herebyincorporated by reference. The composition is typically activated withat least 0.1 J/cm², preferably in the range of from 0.5 J/cm² to 200J/cm² of UV radiation in the range of from 200 nm to 400 nm, preferablyin the range of from 0.5 J/cm² to 100 J/cm², and more preferably in therange of from 0.5 J/cm² to 20 J/cm². The composition can also beactivated with an electron beam at a dosage of about 0.2 to 20 megarads,preferably about 1 to 10 megarads. Other sources of radiation includeionizing radiation, such as gamma, x-rays or corona discharge. Theradiation is preferably conducted in the presence of oxygen.

[0064] The duration of exposure depends on several factors including theamount and type of photoinitiator present, thickness of the layers to beexposed, amount of any antioxidant present, and the wavelength andintensity of the radiation source. The activation is conducted prior tousing the layer or article. Exposure to a flat layer or article providesthe most uniform radiation.

[0065] For many applications, the oxygen scavenging composition cancontain a diluent polymer to provide desired characteristics. Suitablediluent polymers include polyethylene, polypropylene, poly(vinylchloride), and ethylene copolymers such as ethylene-vinyl acetate,ethylene-alkyl acrylates, ethylene-acrylic acid, ethylene-acrylic acidionomers, and mixtures thereof.

[0066] In another aspect of the invention, the oxygen scavengingcomposition comprises a first phase comprising the oxygen scavengingmaterial and a second phase comprising the catalyst. Such compositionsare disclosed in U.S. Ser. No. 08/388,815 filed Feb. 15, 1995, thedisclosure of which is incorporated herein by reference. The first phaseis essentially devoid of catalyst. The second phase is in sufficientlyclose proximity to the first phase to catalyze the oxygen scavengingreaction. When the oxygen scavenging material and the catalyst are inseparate phases, processing difficulties, such as deactivation of thecatalyst or shortened shelf-life, are avoided.

[0067] In another aspect of the invention, the catalyst is incorporatedinto a polymeric material to form at least one catalyst-containinglayer. This layer is then brought into contact with the oxygenscavenging material. The particular polymeric material used is notcritical as long as it does not deactivate the catalyst.

[0068] In another aspect of the invention, the oxygen scavengingcomposition or system can include a polymeric selective barrier layer.Such compositions are disclosed in U.S. Ser. No. 08/304,303 filed Sep.12, 1994, the disclosure of which is incorporated herein by reference.The selective barrier layer functions as a selective barrier to certainoxidation by-products, but does allow the transmission of oxygen.Preferably, the layer prevents at least half of the number and/or amountof oxidation by-products having a boiling point of at least 40° C. frompassing through the polymeric selective barrier layer. Preferably, theselective barrier is located between the packaged item and the oxygenscavenging material.

[0069] The oxygen scavenging composition can also contain an oxygenbarrier layer located on the outside of the scavenging layers to preventthe entry of oxygen into the sealed package. Typical oxygen barriersinclude poly(ethylene vinylalcohol), polyvinylalcohol,polyacrylonitrile, poly(vinyl chloride), poly(vinylidene dichloride),poly(ethylene terephthalate), silica coatings and polyamides such asNylon 6, and Nylon 6,6 and MXD6. Copolymers of certain materialsdescribed above and metal foil layers can also be employed.

[0070] Additional layers such as adhesive layers or heat seal layers mayalso be employed. Adhesive layers include anhydride functionalizedpolyolefins.

[0071] The oxygen scavenging composition can include additives,stabilizers, plasticizers, fillers, pigments, dyestuffs, processingaids, anti-blocks, plasticizers, fire retardants, antifog agents, etc.,which do not interfere with the oxygen scavenging function. Thecomposition can also include antioxidants which inhibit the formation offree radicals and therefore improve storage of the oxygen scavengingcomposition prior to its use in oxygen scavenging applications. Thepresence of such antioxidants inhibits the initiation of the oxygenscavenging reaction until the photoinitiator is activated by radiation.Therefore, the amount employed will depend on the desired storage lifeof the composition, the photoinitiator, and the activation methodemployed.

[0072] The present oxygen scavenging compositions or systems are usefulin improving the shelf-life of packaged oxygen-sensitive products suchas food, pharmaceuticals, cosmetics, chemicals, electronic devices, andhealth and beauty products. The system can be used in rigid containers,flexible bags, or combinations of both. The system can also be used inmoldings, coatings, strip/ribbon, patches, bottle cap inserts, andmolded or thermoformed shapes, such as bottles and trays. In all ofthese applications, the oxygen scavenging composition effectivelyscavenges oxygen, whether it comes from the headspace of the packaging,is entrained in the food or product, or originates from outside thepackage.

[0073] Oxygen scavenging layers and articles are preferably prepared bymelt-blending techniques. However, other methods such as the use of asolvent followed by evaporation may also be employed. When the blendedcomposition is used to make film layers or articles, coextrusion,solvent casting, injection molding, stretch blow molding, orientation,thermoforming, extrusion coating, coating and curing, lamination,extrusion lamination or combinations thereof would typically follow theblending.

[0074] The present invention will now be described further in terms ofcertain examples which are solely illustrative in nature and should inno way limit the scope of the present invention.

EXAMPLES

[0075] Example 1

Tribenzoyl Triphenylbenzene

[0076] The photoinitiator tribenzoyl triphenylbenzene was prepared byplacing 300 mL nitrobenzene, 152 g (1.06 mole) benzoyl chloride, and 100g (0.33 mole) triphenylbenzene into a 2 L 4-necked flask. The mixturewas warmed to about 60° C. and 348 g (2.52 moles) aluminum trichloridewas slowly added over a period of about 1 hour. The temperature rose toabout 80° C. and was maintained for about 4 hours. The mixture wascooled to about 40° C. The reaction mixture was poured into a solutionof 340 g of HCl and 2 L water while stirring vigorously. The mixture wasallowed to stand overnight and the water was decanted. The remainingmixture was filtered, washed with distilled water, and the wet cake wastransferred into a 2 L 3-necked flask equipped with a mechanicalstirrer. To the flask was added 900 mL distilled water. The reactionmixture was vacuum distilled until all nitrobenzene was removed. Thereaction mixture was cooled, filtered and washed with water. The solidtribenzoyl triphenylbenzene was boiled in methanol, cooled and filtered.The solid was dissolved in 350 mL hot chloroform with activated carbonblack and was boiled for 10 minutes and then filtered. The thus-preparedtribenzoyl triphenylbenzene solid was recrystalized again with hotchloroform, washed with methanol, and dried. The product wascharacterized by NMR, UV, IR and exhibited a melting point of 195° C.The molecular weight determined by mass spectrometry was 618.

Benzoylated Styrene Oligomer

[0077] A mixture of styrene trimers was distilled from a polystyreneby-products stream. Then 95 g (0.3 mol) of this trimer mixture wasslowly added to a solution of 218 g (2 moles) of benzoyl chloride and134 g (1 mole) of AlCl₃. After stirring overnight, the mixture waspoured into a solution of 250 g NaOH in 700 ml of water and 100 g of icewith constant stirring. Then 2000 ml of toluene was added to the mixturewhich was stirred an additional 2 hours. The mixture was filtered toremove Al(OH)₃ and the organic layer was washed twice with 500 mlportions of saturated NaCl solution followed by two additional washeswith 1000 ml of distilled water. The organic layer was dried overnightwith MgSO₄. After filtering off the MgSO₄, the solvent was removed undervacuum on a rotary evaporator to yield 112 g of a dark brown, viscousliquid. Analysis of the product showed it comprised a mixture of mono-,di-, and tri-benzoylated compounds. The mixture comprises thenon-extractable photoinitiators dibenzoylated 1,1-diphenyl ethane,di-benzoylated 1,3 diphenyl propane, di-benzoylated 1-phenylnaphthalene, dibenzoylated styrene dimer, and dibenzoylated styrenetrimer.

Ditoluoyl Biphenyl

[0078] The photoinitiator ditoluoyl biphenyl was prepared by placing 300mL nitrobenzene, 38.6 g (0.25 mole) biphenyl, and then 77.3 g (0.5 mole)p-toluoyl chloride into a 1 liter 4-necked flask equipped with a watercondenser. The reaction mixture was cooled to −2° C. While stirring,66.7 g (0.5 mole) aluminum trichloride was added slowly over a period ofabout 20 minutes. During the reaction, the temperature increased to 14°C. The color changed from light yellow to reddish and then to darkgreen. The ice bath was removed and the reaction mixture was stirred atroom temperature for 1 hour. The water bath temperature was increased to67° C. and stirred for 20 hours. The temperature was increased to about90° C. for 3 hours. The reaction mixture was poured with vigorousstirring into 1.2 L of 8% HCl solution. The mixture was stirred for ½hour, then 2 L chloroform was added. The organic layer was separated andwashed with 2×1 L sodium bicarbonate solution followed by 2×1 L water.The organic layer was dried by magnesium sulfate. The solvent wasremoved by vacuum and the remaining solid was washed with 2×200 mLwater. The thus-produced ditoluoyl biphenyl was dissolved in 1 Lchloroform and 800 mL toluene and treated with carbon black. The mixturewas heated for 10 minutes and filtered hot. The thus-produced ditoluoylbiphenyl crystallized out upon cooling and was dried under vacuumovernight.

Dibenzoyl Biphenyl

[0079] The photoinitiator dibenzoyl biphenyl was prepared by placing 200mL nitrobenzene, 38.5 g (0.25 mole) biphenyl, and 140.6 g (1.00 mole)benzoyl chloride into a 1 liter 3-necked flask equipped with a watercondenser. While stirring, 160 g (1.2 mole) aluminum trichloride wasadded slowly over a period of about 30 minutes. During the reaction, thetemperature increased from 30° C. to 55° C. The color changed fromyellowish to light brown, then reddish. The flask was kept in a waterbath at a temperature of 55° C. to 60° C. for 3 hours while stirring.The reaction mixture was then cooled to 35° C. The reaction mixture waspoured into 1.2 L of 8% HCl solution with vigorous stirring. The organiclayer was separated and poured into a blender and 500 mL n-hexane wasadded. The mixture was vigorously stirred for 5 minutes and thenfiltered. The solid was washed with n-hexane. The thus-produceddibenzoyl biphenyl was dried and recrystalized twice in chloroform.

Film Preparation

[0080] Oxidizable resin, carrier resin, catalyst and the photoinitiatorto be evaluated were compounded in a twin screw extruder (Haake RheocordTW-100 or Werner & Pfleiderer ZSK-30) at about 170° C. The carrier resinwas polyethylene, PE1017, from Chevron and the oxidizable resin wasstyrene-butadiene-styrene copolymer, Vector 8508D from Dexco. Thecatalyst was 1000 ppm by weight cobalt in the form of cobalt oleatebased on the total weight of the film. The indicated photoinitiator waspresent in the amount of 1000 ppm based on the total weight of the film.The compounded polymer containing the catalyst and 40% Vector and 60%PE1017 was pelletized. A Randcastle cast film multi-layer micro extruderwas employed to create three-layer films in an “ABA” structure in which“A”, the outer layers, were 0.5 mil Dowlex 3010 polyethylene and “B”,the inner layer, was 1.0 mil of the compounded polymer. Total filmthickness was 2.0 mils.

Head Space Oxygen Absorption

[0081] Samples of 5×20 cm size 3 layer films made above with an averageweight of 0.42 gram were irradiated under a 254 nm UV lamp for a fixedperiod of time (e.g., 1 minute, approximately 600 mJ/cm² of light energymeasured at 254 nm). The film was immediately sealed in an aluminum foilbag which was evacuated and filled with 300 mL 1% oxygen. The oxygencontent was monitored by Mocon oxygen headspace analyzer for a week andoxygen level recorded. The results are graphically represented in FIGS.1 and 2.

Extraction Test

[0082] FDA recommendations for conducting migration (extraction) studiesare found in “Recommendations for Chemistry Data for Indirect FoodAdditive Petitions”, Food & Drug Administration (Chemistry ReviewBranch, Office of Premarket Approval, Center for Food Safety & AppliedNutrition), Washington, D.C. 20204, Jun. 21, 1995.

[0083] Extraction tests were conducted using three methods. In the firstextraction method, Method A, a 5 by 20 cm (15.5 sq. in.) piece of thefilm was irradiated (or not) and placed in a 20 ml headspace vial with14 grams of ethanol. The vials were sealed with a crimped septum cap.The extraction period was 10 days at room temperature. The vials wereopened and the film removed. The extracts were then stored at roomtemperature in the dark before testing.

[0084] In the second extraction method, Method B, a 2-inch diameter filmsample was activated with 800 mJ/cm² UV, then placed in a gas tightcylindrical aluminum extraction cell. The extraction cell was flushedwith gas containing 1% oxygen. A slight positive pressure was produced.Oxygen scavenging was allowed to occur within the cell at roomtemperature for 10 days. The oxygen scavenging results are graphicallyrepresented in FIGS. 1 and 2. Then 12.5 grams 95% ethanol was added toeach cell through a septum. Residual volume of gas was set at 7-8 ml.The cell was inverted to allow contact of ethanol with the oxidized filmand then placed in nitrogen cabinet at room temperature for 11 days. Theextract was removed from the cells using a syringe needle in one septumand pressurizing the cell with nitrogen using a second needle in asecond septum. The extracts were held in the dark at room temperaturebefore testing.

[0085] In the third extraction method, Method C, film was extracted withMiglyol 812 (derived from coconut oil) in an extraction cell asdescribed in Method B at a ratio of 10 g solvent/in². Samples wereextracted at room temperature for 10 days.

[0086] The extracts from all methods were then analyzed forphotoinitiator extractives using gas chromatography (GC-FID) or liquidchromatography (HPLC) methods which were calibrated using standardsolutions of each photoinitiator. Those photoinitiators having lowenough boiling points to permit them to pass through a GC column (DB-1,0.5 mm ID, 60/5/10/300/60° C. temperature program) were analyzed usinggas chromatography. Anthrone, xanthone, 4-benzoyl biphenyl and dibenzoylbiphenyl were determined by gas chromatography. The remaining compoundscould not be analyzed using gas chromatography methods because of theirhigh boiling points. Liquid chromatography methods were used for thesecompounds.

[0087] In Table 1 below:

[0088] ANTH is anthrone.

[0089] XAN is xanthone.

[0090] BBP is 4-benzoyl biphenyl.

[0091] BBDE is 4,4′-bis(benzoyl)-diphenyl ether.

[0092] DBBP is dibenzoyl biphenyl.

[0093] BSO is benzoylated styrene oligomer comprising benzoylatedstyrene dimers, trimers and pentamers.

[0094] BBP³ is tribenzoyl triphenylbenzene.

[0095] DTBP is ditoluoyl biphenyl.

[0096] Good oxygen scavenging compositions consumed half of theavailable oxygen in less than 4 days.

[0097] Fair oxygen scavenging compositions consumed half of theavailable oxygen in 4-5 days.

[0098] Poor oxygen scavenging compositions consumed half of theavailable oxygen in greater than 6 days.

[0099] PI in extract is the amount of photoinitiator in ppb found in theextract (normalized to 10 g simulant/in² film).

[0100] DL is the detection limit defined as 3 times the instrumentsignal noise (normalized to 10 g simulant/in² film). TABLE 1 Days to PIin Photo- reach 0.5% Extraction Triggered Extract DL Run initiatorOxygen Method UV-254 (ppb) (ppb) 101 ANTH  NA* A No 663 7 102 ANTH 4-5 A1 min. 63 7 103 ANTH 4-5 B 1 min. 85 26 201 XAN NA A No 870 6 202 XAN >6A 1 min. 269 6 203 XAN >6 B 1 min. 218 29 301 BBP NA A No 834 6 302 BBP3 A 1 min. 358 6 303 BBP 3 B 1 min. 357 26 401 BBDE NA C 1 min. 1125 50501 DBBP 3-4 A 1 min. 404 8 502 DBBP 3-4 B 1 min. 409 38 601 BSO 2-3 A 1min.  ND** 30 602 BSO 2-3 B 1 min. 100 45 701 BBP³ 2-3 A 1 min. 23 5 702BBP³ 2-3 B 1 min. ND 20 801 DTBP 2-3 A 1 min. ND 7 802 DTBP 2-3 B 1 min.ND 30

[0101] The Table above demonstrates the low leachability of andeffective photoinitiation of the inventive photoinitiators. Runs 101-401are submitted for comparative purposes. It is believed that removal ofsmall molecular weight compounds from the BSO photoinitiator willfurther reduce its leachability.

Example 2

[0102] Three layer films were prepared as described in Example 1 withthe exception of employing 1000 ppm by weight cobalt in the form ofcobalt stearate as catalyst and benzoylated styrene oligomer and4-benzoyl biphenyl individually as photoinitiators. The photoinitiatorswere also present at 1000 ppm by weight based on the oxygen scavengingcomposition.

[0103] The results are graphically represented in FIG. 3. The resultsdemonstrate the effectiveness of cobalt stearate and benzoylated styreneoligomer in providing good oxygen scavenging in a relatively short time.

Example 3 Benzoylated Meta-Terphenyl

[0104] Meta-terphenyl 115 gram (0.5 mole) and benzoyl chloride 232 grams(1.65 mole) were dissolved in 400 ml of nitrobenzene. The reactortemperature is maintained at 40-50° C. while 440 grams of aluminumchloride (3.3 mole) was added in portions to control the exothermicreaction. The reaction mixture was increased to 80° C. for 4 hours andthen poured into 3 L of 5% HCl solution. The product was isolated byrecrystalization from toluene and determined to be di-benzoylatedmeta-terphenyl. The melting point was 205-208° C. The UV spectra wassimilar to monomeric benzophenone. The molecular weight determined bymass spectrometer was 438 g/mole.

What is claimed is:
 1. An oxygen scavenging composition comprising anoxygen scavenging material, a photoinitiator, and at least one catalysteffective in catalyzing oxygen scavenging, wherein the photoinitiatorcomprises at least one benzophenone derivative containing at least twobenzophenone moieties, and wherein the photoinitiator is substantiallynon-extractable when the oxygen scavenging composition is exposed to afood simulant.
 2. The oxygen scavenging composition according to claim 1wherein the photoinitiator is represented by the following formula:X_(m)(Y)_(n) wherein each X is a bridging group selected from the groupconsisting of sulfur; oxygen; carbonyl; —SiR₂—, wherein each R isindividually an alkyl group containing from 1 to 12 carbon atoms, anaryl group containing 6 to 12 carbon atoms, an alkoxy group containingfrom 1 to 12 carbon atoms; —NR′—, wherein R′ is an alkyl groupcontaining 1 to 12 carbon atoms, an aryl group containing 6 to 12 carbonatoms, or hydrogen; and an organic group containing from 1 to 50 carbonatoms; wherein m is 0 to 11; wherein Y is a substituted or unsubstitutedbenzophenone group, wherein each substituent, R″, when present, isindividually an alkyl, aryl, alkoxy, phenoxy, or alicylic groupcontaining from 1 to 24 carbon atoms, or a halide; and wherein n is2-12.
 3. The oxygen scavenging composition according to claim 2 whereinthe combined molecular weight of X plus R″ is at least 30 g/mole.
 4. Theoxygen scavenging composition according to claim 1 wherein less than 250ppb of photoinitiator are extracted through a 0.5 mil polyethylene filmat room temperature from an oxygen scavenging composition containing1000 ppm by weight photoinitiator when exposed to 10 g fatty foodsimulant per square inch of 1 mil film at room temperature after 10days.
 5. The oxygen scavenging composition according to claim 4 whereinless than 100 ppb of photoinitiator are extracted.
 6. The oxygenscavenging composition according to claim 5 wherein less than 50 ppb ofphotoinitiator are extracted.
 7. An oxygen scavenging compositioncomprising an oxygen scavenging material, a photoinitiator, and at leastone catalyst effective in catalyzing oxygen scavenging, wherein thephotoinitiator comprises at least one benzophenone derivative containingat least two benzophenone moieties, and wherein the photoinitiator,after being irradiated with UV light, is substantially non-extractablewhen the oxygen scavenging composition is exposed to a food simulant,and wherein the oxygen scavenging composition has an induction period of1 day or less.
 8. The oxygen scavenging composition according to claim 7wherein less than 250 ppb of photoinitiator are extracted from an oxygenscavenging composition containing 1000 ppm by weight photoinitiator whenexposed to 10 g fatty food simulant per square inch of 1 mil film atroom temperature after 10 days.
 9. The oxygen scavenging compositionaccording to claim 8 wherein less than 100 ppb of photoinitiator areextracted.
 10. The oxygen scavenging composition according to claim 9wherein less than 50 ppb of photoinitiator are extracted.
 11. The oxygenscavenging composition according to claim 8 which consumes half of theavailable oxygen in a container containing 1 percent oxygen in less than4 days at 25° C.
 12. The oxygen scavenging composition according toclaim 11 which consumes half of the available oxygen in a containercontaining 1 percent oxygen in less than 4 days at 4° C.
 13. The oxygenscavenging composition according to claim 12 which exhibits an oxygenscavenging capability of at least 0.1 cc O₂/gram of oxygen scavengingcomposition/day at 25° C.
 14. The oxygen scavenging compositionaccording to claim 13 which exhibits an oxygen scavenging capability ofat least about 0.5 cc O₂/gram of oxygen scavenging composition/day at25° C.
 15. The oxygen scavenging composition according to claim 14 whichexhibits an oxygen scavenging capability of at least about 1 cc O₂/gramof oxygen scavenging composition/day at 25° C.
 16. The oxygen scavengingcomposition according to claim 15 which exhibits an oxygen scavengingcapability of at least about 1 cc O₂/gram of oxygen scavengingcomposition/day at 4° C.
 17. The oxygen scavenging composition of claim16 wherein the photoinitiator has a molecular weight in the range ofabout 360 to about
 5000. 18. The oxygen scavenging composition of claim7 wherein the photoinitiator comprises tribenzoyl triphenylbenzene orsubstituted tribenzoyl triphenylbenzene, wherein the substituents arealkyl, aryl, alkoxy, phenoxy, or alicylic groups containing from 1 to 24carbon atoms or halides.
 19. The oxygen scavenging composition of claim18 wherein the photoinitiator comprises tribenzoyl triphenylbenzene ortritoluoyl triphenylbenzene.
 20. The oxygen scavenging composition ofclaim 7 wherein the photoinitiator comprises benzoylated styreneoligomer or substituted benzoylated styrene oligomer, wherein thesubstituents are alkyl, aryl, alkoxy, phenoxy, or alicylic groupscontaining from 1 to 24 carbon atoms or halides.
 21. The oxygenscavenging composition of claim 20 wherein the photoinitiator comprisesdi-benzoylated styrene trimer, tri-benzoylated styrene pentamer,tetra-benzoylated styrene pentamer or di-benzoylated styrene dimer. 22.The oxygen scavenging composition of claim 7 wherein the photoinitiatorcomprises substituted dibenzoyl biphenyl, wherein the substituents arealkyl, aryl, alkoxy, phenoxy, or alicylic groups containing from 1 to 24carbon atoms or halides.
 23. The oxygen scavenging composition of claim22 wherein the photoinitiator comprises ditoluoyl biphenyl.
 24. Theoxygen scavenging composition of claim 7 wherein the photoinitiatorcomprises benzoylated terphenyl or substituted benzoylated terphenyl,wherein the substituents are alkyl, aryl, alkoxy, phenoxy, or alicylicgroups containing from 1 to 24 carbon atoms or halides.
 25. The oxygenscavenging composition of claim 24 wherein the photoinitiator comprisesdibenzoylated meta-terphenyl.
 26. The oxygen scavenging composition ofclaim 7 wherein the photoinitiator is present in an amount in the rangeof from about 0.001 weight percent to about 10 weight percent based onthe total weight of the oxygen scavenging composition.
 27. The oxygenscavenging composition of claim 26 wherein the photoinitiator is presentin an amount in the range of from about 0.005 weight percent to about 5weight percent based on the total weight of the oxygen scavengingcomposition.
 28. The oxygen scavenging composition of claim 7 whereinthe oxygen scavenging material is an organic compound.
 29. The oxygenscavenging composition of claim 28 wherein the oxygen scavengingmaterial is an ethylenically unsaturated organic compound.
 30. Theoxygen scavenging composition of claim 28 wherein the oxygen scavengingmaterial is an organic polymer.
 31. The oxygen scavenging composition ofclaim 30 wherein the oxygen scavenging material is polybutadiene,polyisoprene, styrene-butadiene block copolymers, acrylates which areprepared by transesterification of poly(ethylene-methyl acrylate), or apolyterpene.
 32. The oxygen scavenging composition of claim 31 whereinthe oxygen scavenging material is poly(alpha-pinene), poly(dipentene),poly(beta-pinene), or poly(limonene).
 33. The oxygen scavengingcomposition of claim 31 wherein the oxygen scavenging material isstyrene-butadiene-styrene block copolymer.
 34. The oxygen scavengingcomposition of claim 7 wherein the oxygen scavenging material is presentin an amount in the range of from about 1 weight percent to about 99weight percent based on the total oxygen scavenging composition.
 35. Theoxygen scavenging composition of claim 34 wherein the oxygen scavengingmaterial is present in an amount in the range of from about 5 weightpercent to about 95 weight percent based on the total oxygen scavengingcomposition.
 36. The oxygen scavenging composition of claim 35 whereinthe oxygen scavenging material is present in an amount in the range offrom 10 weight percent to 90 weight percent based on the total oxygenscavenging composition.
 37. The oxygen scavenging composition of claim 7wherein the catalyst is a transition metal salt.
 38. The oxygenscavenging composition according to claim 37 wherein the catalyst is acobalt salt.
 39. The oxygen scavenging composition according to claim 38wherein the catalyst is cobalt oleate, cobalt linoleate, cobaltneodecanoate, cobalt stearate, or cobalt caprylate.
 40. The oxygenscavenging composition according to claim 39 wherein the catalyst iscobalt oleate.
 41. The oxygen scavenging composition according to claim39 wherein the catalyst is cobalt stearate and the photoinitiator isbenzoylated styrene oligomer or benzoylated m-terphenyl.
 42. The oxygenscavenging composition according to claim 7 wherein the catalyst ispresent in an amount in the range of from about 10 ppm to about 10,000ppm transition metal ion based on the total weight of the oxygenscavenging composition.
 43. The oxygen scavenging composition accordingto claim 7 which is activated with radiation having a wave length in therange of from about 200 about 400 nm.
 44. The oxygen scavengingcomposition according to claim 7 wherein the oxygen scavenging materialcomprises a first phase and the catalyst comprises a second phase,wherein the second phase is in sufficiently close proximity to the firstphase to catalyze an oxygen scavenging reaction.
 45. The oxygenscavenging composition according to claim 44 wherein the first phaseforms a first layer and the second phase forms a second layer.
 46. Theoxygen scavenging composition according to claim 45 wherein the secondlayer is in contact with the first layer.
 47. The oxygen scavengingcomposition according to claim 46 further comprising an oxygen barrierlayer, a selective barrier layer, or a heat seal layer.
 48. A filmcomprising the oxygen scavenging composition of claim
 7. 49. A filmcomprising the oxygen scavenging composition of claim
 45. 50. An articlecomprising the oxygen scavenging composition of claim
 7. 51. The articleof claim 50 wherein the article is a package.
 52. The article of claim51 wherein the article is a package containing a food or beverageproduct, cosmetic, chemical, electronic device, pesticide orpharmaceutical.
 53. The article of claim 50 wherein the article is apatch, bottle cap insert, or molded or thermoformed shape.
 54. Thearticle of claim 53 wherein the molded or thermoformed shape is a bottleor tray.
 55. A method for scavenging oxygen within a package comprisingsealing an oxygen-sensitive product in the package of claim
 47. 56. Themethod of claim 55 wherein the package is activated with at least 0.1J/cm² UV radiation from 200 to 400 nm.
 57. A method for preparing anoxygen scavenging composition comprising melt blending an oxygenscavenging material, a photoinitiator and at least one catalysteffective in catalyzing oxygen scavenging, wherein the photoinitiatorcomprises a benzophenone derivative containing at least two benzophenonemoieties, and wherein the photoinitiator is substantiallynon-extractable when the oxygen scavenging composition is exposed to afood simulant.
 58. A photoinitiator which is tribenzoyl triphenylbenzeneor a substituted tribenzoyl triphenylbenzene, wherein the substituentsare alkyl, aryl, alkoxy, phenoxy, or alicylic groups containing from 1to 24 carbon atoms or halides.
 59. A method for preparing thephotoinitiator of claim 58 comprising reacting a substituted orunsubstituted benzoyl halide with a substituted or unsubstitutedtriphenylbenzene.
 60. A photoinitiator which is benzoylated styreneoligomer or a substituted benzoylated styrene oligomer containing from 2to 12 repeating styrenic groups, wherein the substituents are alkyl,aryl, alkoxy, phenoxy, or alicylic groups containing from 1 to 24 carbonatoms or halides.
 61. The photoinitiator according to claim 60 whereinthe benzoylated styrene oligomer comprises di-benzoylated styrenetrimer, tri-benzoylated styrene pentamer, tetra-benzoylated styrenepentamer, and di-benzoylated styrene dimer.
 62. A method for preparingthe photoinitiator of claim 61 comprising reacting substituted orunsubstituted styrene trimers with substituted or unsubstituted benzoylhalide.
 63. A photoinitiator which is benzoylated meta-terphenyl or asubstituted benzoylated meta-terphenyl.
 64. A method for preparing thephotoinitiator of claim 63 comprising reacting meta-terphenyl orsubstituted meta-terphenyl with benzoyl halide or substituted benzoylhalide.